Merge branch 'tipc_netns_leak'

Ying Xue says:

====================
tipc: fix netns refcnt leak

The series aims to eliminate the issue of netns refcount leak. But
during fixing it, another two additional problems are found. So all
of known issues associated with the netns refcnt leak are resolved
at the same time in the patchset.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 41 insertions, 6 deletions

diff --git a/net/tipc/server.c b/net/tipc/server.c
index eadd4ed45905..ab6183cdb121 100644
--- a/net/tipc/server.c
+++ b/net/tipc/server.c
@@ -37,11 +37,13 @@
 #include "core.h"
 #include "socket.h"
 #include <net/sock.h>
+#include <linux/module.h>
 
 /* Number of messages to send before rescheduling */
 #define MAX_SEND_MSG_COUNT	25
 #define MAX_RECV_MSG_COUNT	25
 #define CF_CONNECTED		1
+#define CF_SERVER		2
 
 #define sock2con(x) ((struct tipc_conn *)(x)->sk_user_data)
 
@@ -88,9 +90,19 @@ static void tipc_clean_outqueues(struct tipc_conn *con);
 static void tipc_conn_kref_release(struct kref *kref)
 {
 	struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
+	struct sockaddr_tipc *saddr = con->server->saddr;
+	struct socket *sock = con->sock;
+	struct sock *sk;
 
-	if (con->sock) {
-		tipc_sock_release_local(con->sock);
+	if (sock) {
+		sk = sock->sk;
+		if (test_bit(CF_SERVER, &con->flags)) {
+			__module_get(sock->ops->owner);
+			__module_get(sk->sk_prot_creator->owner);
+		}
+		saddr->scope = -TIPC_NODE_SCOPE;
+		kernel_bind(sock, (struct sockaddr *)saddr, sizeof(*saddr));
+		sk_release_kernel(sk);
 		con->sock = NULL;
 	}
 
@@ -281,7 +293,7 @@ static int tipc_accept_from_sock(struct tipc_conn *con)
 	struct tipc_conn *newcon;
 	int ret;
 
-	ret = tipc_sock_accept_local(sock, &newsock, O_NONBLOCK);
+	ret = kernel_accept(sock, &newsock, O_NONBLOCK);
 	if (ret < 0)
 		return ret;
 
@@ -309,9 +321,12 @@ static struct socket *tipc_create_listen_sock(struct tipc_conn *con)
 	struct socket *sock = NULL;
 	int ret;
 
-	ret = tipc_sock_create_local(s->net, s->type, &sock);
+	ret = sock_create_kern(AF_TIPC, SOCK_SEQPACKET, 0, &sock);
 	if (ret < 0)
 		return NULL;
+
+	sk_change_net(sock->sk, s->net);
+
 	ret = kernel_setsockopt(sock, SOL_TIPC, TIPC_IMPORTANCE,
 				(char *)&s->imp, sizeof(s->imp));
 	if (ret < 0)
@@ -337,11 +352,31 @@ static struct socket *tipc_create_listen_sock(struct tipc_conn *con)
 		pr_err("Unknown socket type %d\n", s->type);
 		goto create_err;
 	}
+
+	/* As server's listening socket owner and creator is the same module,
+	 * we have to decrease TIPC module reference count to guarantee that
+	 * it remains zero after the server socket is created, otherwise,
+	 * executing "rmmod" command is unable to make TIPC module deleted
+	 * after TIPC module is inserted successfully.
+	 *
+	 * However, the reference count is ever increased twice in
+	 * sock_create_kern(): one is to increase the reference count of owner
+	 * of TIPC socket's proto_ops struct; another is to increment the
+	 * reference count of owner of TIPC proto struct. Therefore, we must
+	 * decrement the module reference count twice to ensure that it keeps
+	 * zero after server's listening socket is created. Of course, we
+	 * must bump the module reference count twice as well before the socket
+	 * is closed.
+	 */
+	module_put(sock->ops->owner);
+	module_put(sock->sk->sk_prot_creator->owner);
+	set_bit(CF_SERVER, &con->flags);
+
 	return sock;
 
 create_err:
-	sock_release(sock);
-	con->sock = NULL;
+	kernel_sock_shutdown(sock, SHUT_RDWR);
+	sk_release_kernel(sock->sk);
 	return NULL;
 }